Expression of a mannose/fucose membrane lectin on human dendritic cells

Dendritic cells (CD) are the most efficient antigen presenting cells for T lymphocytes. CD1a+ CD14- CD with high antigen-presenting capacities can now be obtained easily from adherent peripheral blood monocytes by culture in the presence of granulocyte/macrophage colony-stimulating factor and interleukin-4 (Sallusto et al., J. Exp. Med. 1994. 179: 1109). Human macrophages express a membrane lectin, or sugar-specific receptor, which specifically mediates the binding and endocytosis of mannose- and fucose-terminated glycoproteins and is involved in the phagocytosis of pathogens. A similar lectin activity was sought on cultured human DC using flow cytometry and confocal microscopy to detect binding and internalization of fluoresceinated neoglycoproteins [bovine serum albumin (BSA) substituted with sugar residues]. Several neoglycoproteins, especially alpha-L-fucosyl-, alpha-D-mannosyl-, N,N'-di-acetyl-beta-chitobiosyl- and beta-D-glucosyl-BSA, were endocytosed by cultured human CD1a+ DC as well as by CD1a- CD14- cells which were also obtained in the culture. Fuc-BSA and Man-BSA had the same number of binding sites (1.7 x 10(6)/cell) on CD1a+ DC, and bound with an affinity constant close to 10(7) 1/mol. Inhibition experiments indicated that these two neoglycoproteins bound to the same membrane lectin. CD1a+ and CD1a- cells were both labeled by an antiserum specific for the human macrophage mannose receptor. The membrane lectin specific for mannose and fucose that is evidenced in these experiments on cultured DC may be similar to the macrophage membrane lectin or may share functional and structural properties with it.     

Thermal challenges in next generation electronic systems - summary of panel presentations and discussions

The presentations made, as well as the discussions, in the panels at the workshop, Thermal Challenges in Next Generation Electronic Systems (THERMES), are summarized in this paper. The panels dealt with diverse topics including thermal management roadmaps, microscale cooling systems, numerical modeling from the component to system levels, hardware for future high performance and Internet computing architectures, and transport issues in the manufacturing of electronic packages. The focus of the panels was to identify barriers to further progress in each area that require the attention of the research community.     

Polyimides containing 4,4′‐bipyridinium units

New polyimides containing 4,4′‐bipyridinium units were synthesized by the reaction of bis(dichloromaleimide)arylene derivatives with 4,4′‐bipyridine in meta‐cresol. IR and ¹H‐NMR spectroscopy and elemental analysis as well confirmed their structures. The polymers were characterized by viscometric measurements, softening points, and thermogravimetric data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2091–2100, 2004     

Data collection in global software engineering research: learning from past experience

Global Software Engineering has become a standard in today’s software industry. Research in distributed software development poses severe challenges that are due to the spatial and temporal distribution of the actors, as well as to language, intercultural and organizational aspects. These challenges occur in addition to “traditional” challenges of the domain itself in large-scale software projects, like coordination and communication issues, requirements volatily, lack of domain knowledge, among others. While several authors have reported empirical studies of global software development projects, the methodological difficulties and challenges of this type of studies have not been sufficiently discussed. In this paper, we share our experiences of collecting and analysing qualitative data in the context of Global Software Engineering projects. We discuss strategies for gaining access to field sites, building trust and documenting distributed and complex work practices in the context of several research projects we have conducted in the past 9 years. The experiences described in this paper illustrate the need to deal with fundamental problems, such as understanding local languages and different cultures, observing synchronous interaction, or dealing with barriers imposed by political conflicts between the sites. Based on our findings, we discuss some practical implications and strategies that can be used by other researchers and provide some recommendations for future research in methodological aspects of Global Software Engineering.     

Microfluidic device for continuous magnetophoretic separation of white blood cells

This paper presents a microfluidic device for magnetophoretic separation of red blood cells from blood under continuous flow. The separation method consists of continuous flow of a blood sample (diluted in PBS) through a microfluidic channel which presents on the bottom “dots” of ferromagnetic layer. By applying a magnetic field perpendicular on the flowing direction, the ferromagnetic “dots” generate a gradient of magnetic field which amplifies the magnetic force. As a result, the red blood cells are captured on the bottom of the microfluidic channel while the rest of the blood is collected at the outlet. Experimental results show that an average of 95% of red blood cells is trapped in the device.     

A Novel Class of Symmetric and Nonsymmetric Periodizing Variable Transformations for Numerical Integration

Variable transformations for numerical integration have been used for improving the accuracy of the trapezoidal rule. Specifically, one first transforms the integral via a variable transformation that maps [0,1] to itself, and then approximates the resulting transformed integral by the trapezoidal rule. In this work, we propose a new class of symmetric and nonsymmetric variable transformations which we denote , where r and s are positive scalars assigned by the user. A simple representative of this class is . We show that, in case , or but has algebraic (endpoint) singularities at x = 0 and/or x = 1, the trapezoidal rule on the transformed integral produces exceptionally high accuracies for special values of r and s. In particular, when and we employ , the error in the approximation is (i) O(h ^r ) for arbitrary r and (ii) O(h ^2r ) if r is a positive odd integer at least 3, h being the integration step. We illustrate the use of these transformations and the accompanying theory with numerical examples.      

Betulinic Acid in Complex with a Gamma-Cyclodextrin Derivative Decreases Proliferation and in Vivo Tumor Development of Non-Metastatic and Metastatic B164A5 Cells

Betulinic acid, a very promising anti-melanoma agent, has very low water solubility that causes low bioavailability. To overcome this inconvenience, a highly water-soluble cyclodextrin was used (octakis-[6-deoxy-6-(2-sulfanyl ethanesulfonic acid)]-γ-cyclodextrin). The complex was physico-chemically analyzed using differential scanning calorimetry (DSC), X-ray and scanning electron microscopy (SEM) methods and then in vitro tested for its antiproliferative activity by the MTT assay and by cell cycle analysis. Finally, the complex was tested in vivo using an animal model of murine melanoma developed in C57BL/6J mice, where it caused a reduction in tumor volume and weight. The study revealed the beneficial influence of betulinic acid inclusion into the cyclodextrin in terms of antiproliferative activity and in vivo tumor development.     

Nanofiltration membranes for ionic liquid recovery

Nanofiltration membranes have been developed by interfacial polymerization using base PES ultrafiltration membranes. By varying the concentration of the reactive monomers present as well as the reaction conditions, the structure of the polymerized barrier layer has been modified. Here, the ability to concentrate low molecular weight sugars while allowing dissolved ionic liquids in aqueous solution to be recovered in the permeate has been investigated for application in biomass hydrolysis. The results obtained here indicate that the selectivity for 1-butyl-3-methylimidazoliumchloride (BmimCl) over glucose can be as high as 36.6. The membrane permeance was 2.31 L m^?2 h^?1 bar^?1.     

Modeling and computer simulation of ultrasonic/sonic driller/corer (USDC)

Simulation and analytical models for the ultrasonic/sonic drill/corer (USDC) are described in this paper. The USDC was developed as a tool for in-situ rock sampling and analysis in support of the NASA planetary exploration program. The USDC uses a novel drive mechanism, which transfers ultrasonic vibrations of a piezoelectric actuator into larger oscillations of a free-flying mass (free-mass). The free-mass impact on the drill bit creates a stress pulse at the drill tip/rock interface causing fracture in the rock. The main parts of the device (transducer, free-mass, bit, and rock) and the interactions between them were analyzed and numerically modeled to explore the drive mechanism. Each of these interactions is normally described by a time-dependent 2- or 3-D model involving slowly converging solutions, which makes the conventional approach unsuitable for USDC optimization studies. A simplified integrated model using tabulated data was developed to simulate the operation of the USDC on desktop PC and successfully predicted the characteristics of the device under a variety of conditions. The simulated results of the model and the experimental data used to verify the model are presented.     

Thermal management of high heat flux nanoelectronic chips

Driven by the continuing Moore’s Law evolution in chip technology, power dissipation of nanoelectronics chips could exceed 300W, with heat fluxes above 150W/cm², within the next few years, along with localized, sub-millimeter zones with heat fluxes in excess of 1kW/cm². New and novel cooling techniques, with the ability to selectively cool sub-millimeter “sun spots” while providing effective global cooling for high heat flux chips are needed. Several promising approaches, including the application of miniaturized silicon and BiTe thermoelectric coolers and direct cooling with dielectric liquids through thin film evaporation, will be described.